Evaluate static translation interpolations once in source order

[OskarEichler]

Summary

Evaluate interpolations once, in source order, when using static translation. Capture their rendered values before substituting translated placeholders, matching the existing dynamic translation semantics.

Reproduction

For p #{next_value}, let the translator repeat %1 as %1 %1, and let next_value increment a counter. Static mode currently renders <p>1 2</p> while dynamic mode renders <p>1 1</p>. Reordering or dropping translated placeholders likewise reorders or omits expression evaluation in static mode. After this patch both modes evaluate source expressions once in source order.

Verification

• Unmodified core/plugin suites: 415 runs / 650 assertions passing on Ruby 3.2.11 and 4.0.6; Rails integration 15 runs / 36 assertions passing on each.
• 1,200 focused checks per Ruby cover identity/repeated/reordered/omitted placeholders, expression count/order, escaped values and exact static/dynamic output equivalence.
• Syntax passes; comparative Lint introduces no new offenses. No test files changed.

Compatibility / limitations

No API removal or dependency upgrade. Behavior change: interpolation side effects now happen once in source order, including when a translation omits a placeholder. Applications relying on repeated/skipped/reordered evaluation in static mode will observe the corrected behavior. Translation itself still happens at compile time in static mode.